I have asthma. Thought is was controlled but now collapse sometimes and kept passing out while hiking. Can't breath good. Taking symbicort (budesonide and formoterol) 4 puff day.

Get checked. Asthma attacks can be deadly. Please call 911 or go to the closest emergency room for assessment.
Asthma. Your symptoms of passing out may be more than a case if uncontrolled asthma. See an allergist or possibly a cardiologist to rule out a cardiac problem.
If you are passing. out and collapsing due to asthma - you need emergency medical care. Don't engage in heavy activity until your asthma is better controlled. take care.